What could be the cause of peri-orbital ecchymosis following a vehicular accident?

Periorbital Ecchymosis Following Vehicular Accident: Underlying Causes

Periorbital ecchymosis after a vehicular accident most commonly indicates orbital fracture (particularly orbital roof fractures in younger patients and orbital floor fractures in older patients), but can also result from soft tissue injury alone, basal skull fracture, or direct facial trauma without fracture. 1

Primary Diagnostic Considerations

Orbital Fractures (Most Common Structural Injury)

• Orbital fractures account for 3% to 45% of all pediatric facial fractures and are the second most common isolated facial fracture in adults. 1, 2
• Motor vehicle collisions are among the most common causes of orbital fractures. 1
• Periorbital ecchymosis is a cardinal sign of orbital injury and should prompt immediate assessment for fractures, intracranial hemorrhage, and cranial nerve injury. 1, 3
• The specific fracture pattern varies by age: orbital roof fractures predominate in children <8 years, while orbital floor fractures are more common in older children and adults. 1

Basal Skull Fractures

• Periorbital ecchymosis is classically associated with basal skull fractures, though this represents only a subset of cases. 3
• In one trauma series, 15 of 36 patients (42%) with periorbital ecchymosis had basal skull fractures. 3
• The classic "raccoon eyes" sign with tarsal sparing specifically indicates basal skull fracture, as the orbital septum limits spread of discolouration beyond the tarsal plate. 4
• Other signs of basal skull fracture (Battle's sign, hemotympanum, CSF otorrhea/rhinorrhea) are rarely present alongside periorbital ecchymosis—observed in only 3-7 patients out of 36 in one series. 3

Soft Tissue Injury Without Fracture

• Approximately 25% of patients with traumatic periorbital ecchymosis have soft tissue injuries without any fractures. 3
• Blood tracks along tissue planes into periorbital tissues, causing discolouration in upper and lower eyelids. 3
• Direct trauma to the periorbital region can cause ecchymosis that spreads beyond the tarsal plate, distinguishing it from basal skull fracture patterns. 4

Midface and Zygoma Fractures

• Zygoma fractures are the second most common isolated facial fracture and frequently present with periorbital ecchymosis, facial asymmetry, and enophthalmos. 2, 5
• Blunt force to the zygomatic arch can transmit forces to adjacent structures including the temporal bone. 5
• Midface trauma commonly presents with severe edema, periorbital ecchymosis, enophthalmos, facial asymmetry, and malocclusion. 2

Critical Associated Injuries Requiring Immediate Assessment

Life-Threatening Complications

• Monitor vital signs for bradycardia or heart block, which indicates muscle entrapment causing oculocardiac reflex—a potentially life-threatening condition requiring urgent surgical intervention. 1, 6, 5
• Assess for intracranial hemorrhage, which requires emergent neurosurgical evaluation. 3
• Orbital CSF leak is rare but must be considered when periorbital swelling accompanies orbital roof fractures. 7

Vision-Threatening Injuries

• Globe injury (rupture or laceration) occurs in up to 24% of orbital fractures and must be excluded immediately. 6
• Traumatic optic neuropathy presents with visual loss or visual field defects. 1
• Hyphema, subconjunctival hemorrhage, and restriction of ocular movement are common associated findings. 1

Cranial Nerve Injury

• Cranial nerve injury was the most common clinical feature associated with periorbital ecchymosis in one series, observed in 10 of 36 patients. 3
• Assess facial sensation, extraocular movements, and pupillary responses. 1

Recommended Imaging Algorithm

First-Line Imaging

• CT orbits without contrast is the most useful and accurate imaging modality for evaluating orbital trauma, detecting fractures, soft tissue injuries, hemorrhage, and intraorbital foreign bodies with 94.9% sensitivity. 1
• CT maxillofacial provides high-resolution delineation of osseous and soft-tissue structures for suspected midface injuries. 2, 5
• Thin-section orbital CT with multiplanar reconstructions is superior for identifying integrity of the osseous orbit and skull base. 1

Complementary Imaging

• CT head should be obtained alongside CT orbits when intracranial abnormality or calvarial fracture is suspected, particularly with orbital roof fractures. 1
• MRI is contraindicated if metallic foreign body is suspected but provides superior soft tissue characterization when needed for delayed assessment. 1

Clinical Pitfalls to Avoid

• Do not assume all periorbital ecchymosis indicates basal skull fracture—only 42% of cases in trauma series had this diagnosis. 3
• Periorbital ecchymosis alone does not predict severity; most patients do not require surgical intervention or post-discharge rehabilitation. 3
• Diplopia may be transient, but if unresolved after 6 months, spontaneous resolution is unlikely. 1
• Even minimal-appearing trauma can cause significant orbital injury; the clinical presentation of severe edema may mask underlying fractures. 2